Webster's Revised Unabridged Dictionary · 1913

Justness

Justness , noun

The quality of being just; conformity to truth, propriety, accuracy, exactness, and the like; justice; reasonableness; fairness; equity; as, justness of proportions; the justness of a description or representation; the justness of a cause.
In value the satisfaction I had in seeing it represented with all the justness and gracefulness of action. — Dryden

Justness is properly applied to things, and justice to persons; but the distinction is not always observed.